Can anyone help??????

I have a Legacy turbo which keeps loosing it's boost...

when you rev it up to approx 3200 rpm in any gear there is no boost, you can hear the turbo spinning still and then all of a sudden the power suddenly comes back in, as if someone has opened up a valve and let the power back in again.

this problem could happen at any time...

If anyone has got any suggestions they would be greatly received.

Many Thanks

 

My Legacy had something similar once -

The circlip connecting the actuator arm to the wastgate had popped off and the arm was sometimes slipping past the wastgate linkage getting no boost, other times it catch and be ok. (check under the turbo heat shield to see if its secure).

other than that check the usual - e.g. hoses are secure with no cracks etc.

(had one of the hoses blow off the manifold once with loss of boost)

Another thought - could be a sticky actuator, getting occasionally stuck when it's arm's extended - leaking away low rpm boost (this is unlikely tho becuase the return springs are usually quite strong).

[Edited by Richard Curtis - 12/24/2001 2:27:40 AM]

 

Thaks Richard,

but i have tried both of these with no success.???

Any other ideas?

 

Next step -

pop this post on the drivetrain section with a header such as 'erratic boost - help!'

There are plenty of experts on here - u just have to keep plugging away until u get their attention. Meanwhile I'll have another think and see if anything else comes to mind.

Another thought - If you can hear the turbo spinning but no power, it may be the blow off valve (also called dump valve) sticking open - re-circulating the compressed air back into the intake and thus losing boost. I had a problem with the valve on my Impreza (after i sold legacy) but it was not as severe as your problems, the valve was not shutting properly and making a bottle blowing noise.

Rich


[Edited by Richard Curtis - 12/28/2001 12:42:24 AM]